diff --git a/fonts/pixel_font.cpp b/fonts/pixel_font.cpp
index fc6d69b..37b7e68 100644
--- a/fonts/pixel_font.cpp
+++ b/fonts/pixel_font.cpp
@@ -2,6 +2,7 @@
 #include <fonts/pixel_font.h>
 #include <graphics/draw.h>
 #include <common.h>
+#include <string_utils.h>
 
 void pf_print_char(char c, SUINT32 basex, SUINT32 basey, EFI_GRAPHICS_OUTPUT_BLT_PIXEL color) {
     for (SUINT32 y = 0; y < 16; y++) {
@@ -23,7 +24,7 @@ void pf_print_char(char c, SUINT32 basex, SUINT32 basey, EFI_GRAPHICS_OUTPUT_BLT
 }
 
 void pf_print(const char* text, SUINT32 basex, SUINT32 basey, EFI_GRAPHICS_OUTPUT_BLT_PIXEL color) {
-    for (SUINT32 i = 0; i < strlen(text); i++) {
+    for (SUINT32 i = 0; i < str_len(text); i++) {
         char c = text[i];
         pf_print_char(c, basex + i * 8, basey, color); // 只要 字数 * 8 + basex 不爆hr就没事
     }
diff --git a/include/common.h b/include/common.h
index ccecc24..8f3c7e9 100644
--- a/include/common.h
+++ b/include/common.h
@@ -1,10 +1,5 @@
 #pragma once
 
 #include <types.h>
-#define ASM asm volatile
-
-static SUINT32 strlen(const char* arr) { // 获取string长度
-    SSINT32 i = 0;
-    while (arr[i++] != '\0');
-    return i - 1;
-}
\ No newline at end of file
+#include <string_utils.h>
+#define ASM asm volatile
\ No newline at end of file
diff --git a/include/fonts/pixel_font.h b/include/fonts/pixel_font.h
index 02faf58..0436bf1 100644
--- a/include/fonts/pixel_font.h
+++ b/include/fonts/pixel_font.h
@@ -1,7 +1,8 @@
 #pragma once
 
 #include <graphics/context.h>
+#include <string_utils.h>
 
 void pf_print_char(char c, SUINT32 basex, SUINT32 basey,
         EFI_GRAPHICS_OUTPUT_BLT_PIXEL color = {255, 255, 255, 255});                         // Pixel Font 打印字符
-void pf_print(const char* text, SUINT32 basex, SUINT32 basey, EFI_GRAPHICS_OUTPUT_BLT_PIXEL color = {255, 255, 255, 255}); // Pixel Font 打印string
\ No newline at end of file
+void pf_print(String text, SUINT32 basex, SUINT32 basey, EFI_GRAPHICS_OUTPUT_BLT_PIXEL color = {255, 255, 255, 255}); // Pixel Font 打印string
\ No newline at end of file
diff --git a/include/fs.h b/include/fs.h
index c7df69f..59a1657 100644
--- a/include/fs.h
+++ b/include/fs.h
@@ -1,6 +1,7 @@
 #pragma once
 #include <efi.h>
+#include <string_utils.h>
 
 EFI_STATUS fs_init();
 void fs_list();
-EFI_STATUS fs_read(const CHAR16 *Path, void **Buffer, UINTN *Size);
+EFI_STATUS fs_read(WString Path, void **Buffer, UINTN *Size);
diff --git a/include/graphics/layer.h b/include/graphics/layer.h
index 2ede234..665b3c9 100644
--- a/include/graphics/layer.h
+++ b/include/graphics/layer.h
@@ -2,6 +2,7 @@
 
 #include <efi.h>
 #include <common.h>
+#include <string_utils.h>
 
 #define LAYER_MAX 32
 #define LAYER_NAME_LEN 32
@@ -29,7 +30,7 @@ typedef struct layer {
 void layer_init(void);
 
 // Layer management
-layer_t* layer_create(const char* name, layer_type_t type, UINT32 w, UINT32 h);
+layer_t* layer_create(String name, layer_type_t type, UINT32 w, UINT32 h);
 void     layer_destroy(layer_t* layer);
 void     layer_set_z(layer_t* layer, SSINT32 z);
 void     layer_set_pos(layer_t* layer, SSINT32 x, SSINT32 y);
diff --git a/include/scheduler.h b/include/scheduler.h
index 2165d78..dd3d6e7 100644
--- a/include/scheduler.h
+++ b/include/scheduler.h
@@ -3,6 +3,7 @@
 #include <efi.h>
 #include <memory/pmm.h>
 #include <common.h>
+#include <string_utils.h>
 
 #define TASK_STACK_SIZE  (PAGE_SIZE * 4)  // 16 KB kernel stack per task
 #define TASK_MAX         32
@@ -26,7 +27,7 @@ typedef struct task {
 } task_t;
 
 // Create a new task. Returns task pointer or NULL on failure.
-task_t* task_create(const char* name, void (*entry)(void));
+task_t* task_create(String name, void (*entry)(void));
 
 // Yield CPU to next ready task (cooperative)
 void yield(void);
diff --git a/include/serial.h b/include/serial.h
index 6cfccc7..72f296c 100644
--- a/include/serial.h
+++ b/include/serial.h
@@ -2,6 +2,7 @@
 
 #include <efi.h>
 #include <efiser.h>
+#include <string_utils.h>
 
 struct serial_context { // 串行内容结构体
     EFI_SERIAL_IO_PROTOCOL *SerialIo;
@@ -10,7 +11,7 @@ struct serial_context { // 串行内容结构体
 extern serial_context g_serial;
 
 void serial_init(EFI_SERIAL_IO_PROTOCOL *SerialIo); // 初始化串行驱动
-void serial_write(const char *str);                 // 往串行写string
+void serial_write(String str);                      // 往串行写string
 void serial_write_char(char c);                     // 往串行写char（不推荐使用）
 void serial_write_hex(UINTN val);                   // 往串行写十六进制数字
 char serial_read_char();                            // 读串行
\ No newline at end of file
diff --git a/include/string_utils.h b/include/string_utils.h
new file mode 100644
index 0000000..f8e9be9
--- /dev/null
+++ b/include/string_utils.h
@@ -0,0 +1,91 @@
+#pragma once
+
+#include <types.h>
+
+// === Unified string types ===
+// Use these throughout the kernel instead of raw char*/const char*.
+
+typedef const char* String;       // 8-bit narrow string
+typedef const uint16_t* WString;  // 16-bit wide string (CHAR16)
+
+// === Narrow string utilities (String) ===
+
+static inline SUINT32 str_len(String s) {
+    SUINT32 i = 0;
+    while (s[i]) i++;
+    return i;
+}
+
+static inline SSINT32 str_cmp(String a, String b) {
+    while (*a && *a == *b) { a++; b++; }
+    return (SUINT8)*a - (SUINT8)*b;
+}
+
+static inline bool str_eq(String a, String b) {
+    return str_cmp(a, b) == 0;
+}
+
+// Copy up to max-1 chars, always null-terminates.
+static inline void str_copy(char* dst, String src, SUINT32 max) {
+    if (max == 0) return;
+    SUINT32 i = 0;
+    while (src[i] && i < max - 1) {
+        dst[i] = src[i];
+        i++;
+    }
+    dst[i] = '\0';
+}
+
+// === Wide string utilities (WString) ===
+
+static inline SUINT32 wstr_len(WString s) {
+    SUINT32 i = 0;
+    while (s[i]) i++;
+    return i;
+}
+
+static inline SSINT32 wstr_cmp(WString a, WString b) {
+    while (*a && *a == *b) { a++; b++; }
+    return (SUINT16)*a - (SUINT16)*b;
+}
+
+static inline bool wstr_eq(WString a, WString b) {
+    return wstr_cmp(a, b) == 0;
+}
+
+static inline void wstr_copy(uint16_t* dst, WString src, SUINT32 max) {
+    if (max == 0) return;
+    SUINT32 i = 0;
+    while (src[i] && i < max - 1) {
+        dst[i] = src[i];
+        i++;
+    }
+    dst[i] = 0;
+}
+
+// Convert wide string to ASCII (non-printable -> '?')
+static inline void wstr_to_ascii(char* dst, WString src, SUINT32 max) {
+    if (max == 0) return;
+    SUINT32 i = 0;
+    while (src[i] && i < max - 1) {
+        if (src[i] >= 0x20 && src[i] <= 0x7E)
+            dst[i] = (char)src[i];
+        else
+            dst[i] = '?';
+        i++;
+    }
+    dst[i] = '\0';
+}
+
+// === Memory utilities ===
+
+static inline void mem_set(void* dst, SUINT8 val, SUINT32 size) {
+    SUINT8* d = (SUINT8*)dst;
+    for (SUINT32 i = 0; i < size; i++) d[i] = val;
+}
+
+static inline void mem_copy(void* dst, const void* src, SUINT32 size) {
+    SUINT8* d = (SUINT8*)dst;
+    const SUINT8* s = (const SUINT8*)src;
+    for (SUINT32 i = 0; i < size; i++) d[i] = s[i];
+}
diff --git a/kernel/fs.cpp b/kernel/fs.cpp
index 3f3e421..a1b1ffd 100644
--- a/kernel/fs.cpp
+++ b/kernel/fs.cpp
@@ -1,7 +1,7 @@
 #include <fs.h>
 #include <serial.h>
 #include <memory/heap.h>
-#include <common.h>
+#include <string_utils.h>
 
 extern EFI_SYSTEM_TABLE *ST;
 
@@ -537,14 +537,7 @@ struct list_ctx {
 };
 
 static void name_to_ascii(const CHAR16 *Name, char *Ascii, UINTN ascii_sz) {
-    UINTN i = 0;
-    for (; Name[i] && i < ascii_sz - 1; i++) {
-        if (Name[i] >= 0x20 && Name[i] <= 0x7E)
-            Ascii[i] = (char)Name[i];
-        else
-            Ascii[i] = '?';
-    }
-    Ascii[i] = 0;
+    wstr_to_ascii(Ascii, (WString)Name, ascii_sz);
 }
 
 static void list_callback(void *ctx, const CHAR16 *Name, UINT8 Attr,
@@ -633,10 +626,7 @@ struct find_ctx {
 };
 
 static BOOLEAN name_match(const CHAR16 *a, const CHAR16 *b) {
-    UINTN i = 0;
-    for (; a[i] && b[i]; i++)
-        if (a[i] != b[i]) return FALSE;
-    return a[i] == 0 && b[i] == 0;
+    return wstr_eq((WString)a, (WString)b);
 }
 
 static void find_callback(void *ctx, const CHAR16 *Name, UINT8 Attr,
@@ -651,7 +641,7 @@ static void find_callback(void *ctx, const CHAR16 *Name, UINT8 Attr,
     }
 }
 
-EFI_STATUS fs_read(const CHAR16 *Path, void **Buffer, UINTN *Size) {
+EFI_STATUS fs_read(WString Path, void **Buffer, UINTN *Size) {
     if (!g_fs_inited) return EFI_NOT_READY;
 
     const CHAR16 *p = Path;
diff --git a/kernel/graphics/layer.cpp b/kernel/graphics/layer.cpp
index 9f3aabc..3d51a59 100644
--- a/kernel/graphics/layer.cpp
+++ b/kernel/graphics/layer.cpp
@@ -7,7 +7,7 @@
 #include <serial.h>
 #include <idt.h>
 #include <pic.h>
-#include <common.h>
+#include <string_utils.h>
 
 // --- Layer list (sorted by z, lowest first) ---
 
@@ -84,12 +84,7 @@ layer_t* layer_create(const char* name, layer_type_t type, UINT32 w, UINT32 h) {
     layer->visible = true;
     layer->next = NULL;
 
-    const char* s = name;
-    char* d = layer->name;
-    for (SSINT32 i = 0; i < LAYER_NAME_LEN - 1 && *s; i++) {
-        *d++ = *s++;
-    }
-    *d = '\0';
+    str_copy(layer->name, name, LAYER_NAME_LEN);
 
     UINTN buf_size = (UINTN)w * h * sizeof(EFI_GRAPHICS_OUTPUT_BLT_PIXEL);
     layer->buffer = (EFI_GRAPHICS_OUTPUT_BLT_PIXEL*)kmalloc(buf_size);
diff --git a/kernel/interrupt/gdt.cpp b/kernel/interrupt/gdt.cpp
index 97c9089..139446c 100644
--- a/kernel/interrupt/gdt.cpp
+++ b/kernel/interrupt/gdt.cpp
@@ -1,5 +1,6 @@
 #include <gdt.h>
 #include <common.h>
+#include <string_utils.h>
 #include <serial.h>
 
 static gdt_entry g_gdt[7];  // 5 segments + TSS (2 entries)
diff --git a/kernel/interrupt/idt.cpp b/kernel/interrupt/idt.cpp
index 2cbd303..3379b89 100644
--- a/kernel/interrupt/idt.cpp
+++ b/kernel/interrupt/idt.cpp
@@ -1,5 +1,6 @@
 #include <idt.h>
 #include <common.h>
+#include <string_utils.h>
 #include <pic.h>
 #include <serial.h>
 
diff --git a/kernel/interrupt/pic.cpp b/kernel/interrupt/pic.cpp
index 6fb5d27..298232a 100644
--- a/kernel/interrupt/pic.cpp
+++ b/kernel/interrupt/pic.cpp
@@ -1,5 +1,6 @@
 #include <pic.h>
 #include <common.h>
+#include <string_utils.h>
 #include <serial.h>
 
 static inline void outb(UINT16 port, UINT8 val) {
diff --git a/kernel/interrupt/pit.cpp b/kernel/interrupt/pit.cpp
index 1389506..4871437 100644
--- a/kernel/interrupt/pit.cpp
+++ b/kernel/interrupt/pit.cpp
@@ -1,5 +1,6 @@
 #include <pit.h>
 #include <common.h>
+#include <string_utils.h>
 #include <pic.h>
 #include <serial.h>
 
diff --git a/kernel/main.cpp b/kernel/main.cpp
index 457aa66..0aa185f 100644
--- a/kernel/main.cpp
+++ b/kernel/main.cpp
@@ -5,6 +5,7 @@
 #include <fonts/pixel_font.h>
 #include <serial.h>
 #include <common.h>
+#include <string_utils.h>
 #include <memory/pmm.h>
 #include <memory/heap.h>
 #include <scheduler.h>
diff --git a/kernel/memory/heap.cpp b/kernel/memory/heap.cpp
index 5053c7c..cc581bd 100644
--- a/kernel/memory/heap.cpp
+++ b/kernel/memory/heap.cpp
@@ -1,6 +1,7 @@
 #include <memory/heap.h>
 #include <memory/pmm.h>
 #include <serial.h>
+#include <string_utils.h>
 
 struct heap_block {
     UINTN  size;   // includes header; bit 0 = 1 used, 0 free
@@ -184,10 +185,7 @@ void* kcalloc(UINTN num, UINTN size) {
     UINTN total = num * size;
     void* ptr = kmalloc(total);
     if (ptr) {
-        UINT8* p = (UINT8*)ptr;
-        for (UINTN i = 0; i < total; i++) {
-            p[i] = 0;
-        }
+        mem_set(ptr, 0, total);
     }
     return ptr;
 }
@@ -216,11 +214,7 @@ void* krealloc(void* ptr, UINTN new_size) {
 
     void* new_ptr = kmalloc(new_size);
     if (new_ptr) {
-        UINT8* src = (UINT8*)ptr;
-        UINT8* dst = (UINT8*)new_ptr;
-        for (UINTN i = 0; i < old_size; i++) {
-            dst[i] = src[i];
-        }
+        mem_copy(new_ptr, ptr, old_size);
         kfree(ptr);
     }
     return new_ptr;
diff --git a/kernel/memory/pmm.cpp b/kernel/memory/pmm.cpp
index 85ae72a..d3cec15 100644
--- a/kernel/memory/pmm.cpp
+++ b/kernel/memory/pmm.cpp
@@ -1,5 +1,7 @@
 #include <memory/pmm.h>
+#include <common.h>
 #include <serial.h>
+#include <string_utils.h>
 
 extern EFI_SYSTEM_TABLE *ST;
 
diff --git a/kernel/scheduler/scheduler.cpp b/kernel/scheduler/scheduler.cpp
index 9aa73ad..52e5c02 100644
--- a/kernel/scheduler/scheduler.cpp
+++ b/kernel/scheduler/scheduler.cpp
@@ -53,12 +53,7 @@ task_t* task_create(const char* name, void (*entry)(void)) {
     task->time_slice = TIME_SLICE_DEFAULT;
 
     // Copy name
-    const char* s = name;
-    char* d = task->name;
-    for (SSINT32 i = 0; i < TASK_NAME_LEN - 1 && *s; i++) {
-        *d++ = *s++;
-    }
-    *d = '\0';
+    str_copy(task->name, name, TASK_NAME_LEN);
 
     // Set up initial stack for first context_switch into this task.
     // Stack grows downward. context_switch will pop 6 regs then ret.
diff --git a/kernel/serial.cpp b/kernel/serial.cpp
index 2a00a64..15e494e 100644
--- a/kernel/serial.cpp
+++ b/kernel/serial.cpp
@@ -1,5 +1,5 @@
 #include <serial.h>
-#include <common.h>
+#include <string_utils.h>
 
 extern EFI_SYSTEM_TABLE *ST;
 
@@ -22,7 +22,7 @@ void serial_write_char(char c) {
     }
 }
 
-void serial_write(const char *str) {
+void serial_write(String str) {
     if (!g_serial.SerialIo) {
         uefi_call_wrapper(ST->ConOut->OutputString, 2, ST->ConOut, (CHAR16*)L"serial: null io\n");
         return;